In this research project, we have so far obtained the following findings. First, by using a liquid chromatography-electrospray ionization mass spectrometry method, we analyzed sphingolipids in Madin-Darby Canine Kidney (MDCK) cysts under various conditions. Our result showed that, compared to the three-dimensional cyst, the two-dimensional MDCK sheet is relatively enriched in sphingolipids. During cystogenesis, or upon the switching on of activated K-Ras expression in MDCK cysts, lipid contents were altered (J Biochem., in press). Second, we performed a microarray analysis comparing the mRNA expression between the early and late stages of MDCK cystogenesis. We found that one of the gene candidates, Ripply1, was expressed higher in the late stages. Unexpectedly, we found that the Ripply1 protein is degraded by the proteasome system. Mutant analysis suggests that Ripply1 is not ubiquitinated directly, but rather is degraded only after binding to Transducin-like Enhancer of Split 1, a transcriptional repressor. Live-imaging revealed that Ripply1 is degraded in the nucleus, and this degradation is inhibited during the mitosis (BBRC, 2015). Third, we isolated the liver-metastatic prone clone from colon26 cells, which was derived from mouse colon cancer tissue with K-Ras mutation. We named this clone as LM4, and found that it invaded the liver from the large portal vein, while colon26 metastasized at the periphery of the liver. In vitro, LM4 showed square-like shape, while the parent colon26 was spindle. LM4 produced more cytokines and growth factors than colon26 did. Using LM4 with fluorescent biosensors, we started to observe the extra-vasation process in the living mouse (Unpublished). Fourth, we established the MDCK cysts imaging system for several days in vitro, and have started the drug screening which suppresses coherent rotation of the cysts (Unpublished).